The present invention relates to an apparatus and method for servicing refrigeration systems and particularly to a system which includes the automatic draining of recovered oil from an oil accumulator.
During servicing of refrigeration circuits, such as the air conditioning system of a vehicle, upon evacuating the circuit, lubricating oil contained within the refrigerant is also withdrawn. During the recovery and evacuation steps, old oil is separated from the refrigerant by an accumulator or oil separator. The separated oil is collected in a graduated container allowing measurement of removed oil and permitting the operator to recharge the system with additional fresh oil equivalent to that removed.
U.S. Pat. No. 4,364,236 discloses an oil recovery system in which the oil recovered from a separator is collected in a graduated bottle utilizing a manually operated control valve. Although this system accurately measures the recovered oil, it requires intervention of the operator of the system as well as requiring time to allow the oil to drain once the manually operated valve is opened. An improvement to the manually operated valve incorporates a solenoid valve which is opened for a selected period of time to drain oil from the oil separator. In order to fully drain the oil, it was necessary, however, to select a time period which frequently allowed excess loss of refrigerant.
There remains a need, therefore, for an oil recovery system in which oil separated from a refrigerant circuit is automatically drained into a measurement vessel during the recovery process without loss of refrigerant.